JP6661366B2 - Container manufacturing method - Google Patents

Description

The present invention relates to a preform having a permeability at least an inner surface is formed of a polyester and liquid blow molding the container manufacturing how to manufacture the container of a predetermined shape containing the liquid contents therein.

  Transparent (transparent) polyester containers such as polyethylene terephthalate bottles (pet bottles) and polyethylene naphthalate containers are used for beverages, cosmetics, chemicals, liquid detergents, toiletries such as shampoos, etc. Used for containing various liquids.

  Such a container is generally manufactured by blow-molding a permeable preform made of polyester formed into a substantially test tube. Further, as blow molding for molding a preform into a container, there is known liquid blow molding in which a pressurized liquid (pressurized liquid) is used instead of pressurized air as a pressurized medium supplied to the preform. I have.

  For example, Patent Literature 1 describes a method of manufacturing a container having a predetermined shape by supplying a pressurized liquid to a preform made of polyethylene terephthalate, which is a kind of polyester, by subjecting the preform to liquid blow molding. . In such a container manufacturing method using liquid blow molding, by using the content liquid finally contained in the container as a liquid to be supplied to the preform, the filling process of the container with the content liquid after molding is performed. By omitting, the manufacturing process and the configuration of the molding and filling line can be simplified.

JP-T-2005-529002

  When manufacturing a container containing a liquid containing a surfactant such as a liquid detergent or a softener or an alcohol-containing liquid containing an alcohol such as ethanol as an alcoholic beverage as a content liquid, a polyester preform is used. Is supplied as a pressurized medium to perform liquid blow molding.

  However, when a liquid containing a surfactant or a liquid containing an alcohol is supplied to a polyester preform and liquid blow molding is performed, the inner surface of the preform is attacked by the surfactant or the alcohol during the molding, and after the molding, Fine irregularities are formed on the inner surface of the container. For this reason, there has been a problem that cloudiness (cloudiness) occurs on the inner surface of the container and the permeability of the container is impaired. This is not only the case where a single-layer preform made of only polyester is subjected to liquid blow molding, but also, for example, the innermost layer is formed of a polyester layer, and a different polyester layer or another resin layer is laminated on the outer layer. The same applies to the case where a preform having at least an inner surface made of polyester, such as a preform having a laminated structure, is subjected to liquid blow molding.

The present invention has been made in view of such a problem, and an object of the present invention is to form a permeable preform having at least an inner surface formed of polyester with a liquid containing a surfactant or a liquid containing alcohol. it is blow molded, is to provide a container manufacturing how that can ensure permeability of the container after molding for accommodating the liquid.

The container manufacturing method of the present invention includes a preform molding step of molding a preform having at least an inner surface formed of polyester and having permeability, and covering the inner surface of the preform with a coating layer having ductility and water insolubility. a covering step, have a, a liquid blow-molding process for molding a container having a predetermined shape the preform to supply internal to the pressurized liquid of the preform inside surface is coated by the coating layer, the pressure As the liquid, an erosion liquid that contains at least one of an alkali component, a surfactant, and an alcohol component such as ethanol at a predetermined weight concentration or more and erodes the polyester to make the surface of the polyester cloudy is used. It is characterized by that.

  In the container manufacturing method of the present invention, in the above configuration, it is preferable that the preform is formed of polyethylene terephthalate.

  In the container manufacturing method of the present invention, in the above-described configuration, it is preferable that the coating layer is formed of polyvinyl butyral.

  In the container manufacturing method of the present invention, in the above configuration, it is preferable that the coating layer is formed of polyvinylidene chloride.

  According to the present invention, at least the inner surface of the permeable preform formed of polyester is coated with a coating layer having ductility and water insolubility, so that the liquid blow molding contains a surfactant. Even when a liquid or alcohol-containing liquid is supplied into the preform, the coating layer can protect the inner surface of the preform from the liquid. In addition, by adopting a coating layer having ductility and water insolubility, the coating layer is stretched together with the preform during liquid blow molding, so that the inner surface of the preform or container is always protected from the liquid by the coating layer. can do. Therefore, during the liquid blow molding, the inner surface of the preform or the container formed of polyester is prevented from being attacked by the liquid containing the surfactant or the liquid containing the alcohol, whereby the formed container becomes cloudy (cloudy). Can be prevented, and the permeability of the molded container can be ensured.

As described above, according to the present invention, even if a liquid-containing preform having at least the inner surface formed of polyester is subjected to liquid blow molding with a liquid containing a surfactant or an alcohol-containing liquid, the liquid may be used. container manufacturing how the permeability of the container after molding can be secured for housing can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows the liquid blow molding apparatus used for the container manufacturing method which is one Embodiment of this invention. It is explanatory drawing which shows a mode that the preform is performing the liquid blow molding.

  Hereinafter, the present invention will be described more specifically with reference to the drawings.

  The container manufacturing method of the present invention comprises a preform molding step of molding a preform having at least an inner surface formed of polyester and having permeability, and coating the inner surface of the preform with a coating layer having ductility and water insolubility. And a liquid blow molding step of supplying a pressurized liquid to the inside of the preform, the inner surface of which is covered by the coating layer, and molding the preform into a container having a predetermined shape. .

  In the present invention, “having permeability” means that a liquid (content liquid) contained in a preform or a container can be visually recognized from the outside, and various colors such as colorless or colored, transparent or translucent, and the like. Including things.

  In the container manufacturing method of the present invention, first, a preform molding step is performed. In the preform molding step, a preform PF having transparency and at least an inner surface formed of polyester is molded.

  In the preform molding step, a preform PF having a predetermined shape can be formed by performing injection molding, direct blow molding, extrusion molding, or the like using polyester (resin) as a raw material. In this case, as shown in FIG. 1, for example, the shape of the preform PF can be a substantially test tube having a cylindrical mouth PFa and a bottomed cylindrical body PFb connected to the mouth PFa. .

  Note that the shape of the preform PF can be variously changed as long as the preform PF can be subjected to liquid blow molding to manufacture a container for containing the content liquid.

  The preform PF molded in the preform molding step may have a single-layer structure made of, for example, polyethylene terephthalate (PET). In this case, by performing liquid blow molding of the preform PF, a container for containing the content liquid can be configured as a so-called PET bottle.

  In addition, the material of the preform PF is not limited to polyethylene terephthalate, and other materials such as polyethylene naphthalate (PEN) can be used as long as it is a polyester having transparency.

  Further, the preform PF is not limited to a single-layer structure as long as at least the inner surface thereof is formed of polyester and has transparency, for example, polyester is used as the innermost layer, and different polyesters and other resins are provided on the outer side. A layered structure in which layers are stacked can also be used.

  When the preform PF is formed in the preform forming step, a covering step is performed next. In the covering step, the covering layer S is provided on the inner surface of the preform PF formed in the preform forming step, and the entire inner surface is covered with the covering layer S.

  The coating layer S has the property of being insoluble in water, that is, having a property of being hardly soluble in water, and has a predetermined stretching ratio together with the preform PF when the preform PF is formed into a container by liquid blow molding, in the axial direction and the radial direction. A material having ductility that can be stretched is used.

  For example, the coating layer S may be formed of polyvinyl butyral (PVB). In this case, it is preferable that the coating layer S has a configuration in which a thin film of polyvinyl butyral is laminated and arranged in a state of being in close contact with the entire inner surface of the preform PF.

  Such a coating layer S is formed, for example, by applying liquid polyvinyl butyral to the entire inner surface of the preform PF by spraying or by injecting the liquid polyvinyl butyral into the preform PF and then discharging the preform PF. Can be formed by immersing in a liquid polyvinyl butyral or applying polyvinyl butyral to the entire inner surface of the preform PF, and then drying the polyvinyl butyral. In addition, a diluting liquid may be used as the polyvinyl butyral.

  The coating layer S is not limited to polyvinyl butyral (PVB), but may be made of various materials such as polyvinylidene chloride (PVDC) and polyurethane as long as it has ductility and water insolubility. Can also be adopted.

  It is preferable that the coating layer S has permeability, but when the preform PF is formed into a container, the preform PF is stretched together with the preform PF so as to have a reduced thickness and thus has transparency. If so, the preform PF may not have transparency when provided on the inner surface.

  Thus, the preform PF having the inner surface covered with the coating layer S is manufactured by the preform molding step and the covering step.

  When the preform PF in which the inner surface is covered with the coating layer S is manufactured, next, a liquid blow molding step is performed. In the liquid blow molding step, as shown in FIG. 2, a liquid pressurized to a predetermined pressure, that is, a pressurized liquid L, is supplied into the preform PF, and the preform PF is placed in a container C having a predetermined shape. Molding. The inner surface of the molded container C is entirely covered with a coating layer S that has been stretched together with the preform PF.

  In the liquid blow molding step, as the pressurized liquid L, for example, an alkali component, a surfactant, an alcohol component such as ethanol, or the like, when the pressurized liquid L is contained in the pressurized liquid L at a ratio of a predetermined weight concentration or more, the polyester is eroded. A liquid containing a component that makes the surface cloudy (hereinafter, referred to as an erosion liquid) can be used. In this case, the erosion liquid may contain a plurality of types of components as described above in any combination, and may further contain other components such as preservatives, coloring agents, enzymes, and fragrances. You can also. Examples of such an erosion liquid include various liquids such as a liquid detergent, a softener, and an alcoholic beverage. In the following embodiment, a case where the above-described erosion liquid is used as the pressurized liquid L will be described.

  The liquid blow molding step can be performed using, for example, a liquid blow molding apparatus 1 as shown in FIGS. The liquid blow molding apparatus 1 accommodates the erosion liquid by performing liquid blow molding of the preform PF having the inner surface covered with the coating layer S using the pressurized liquid L made of the erosion liquid described above. A container C having a predetermined shape can be manufactured.

  The liquid blow molding apparatus 1 has a blow mold 11. The blow mold 11 has a cavity 12 having a shape corresponding to the shape of the container C. In the illustrated case, the cavity 12 is formed in a bottle shape, and opens upward on the upper surface of the blow mold 11. Although not shown in detail, the blow mold 11 can be opened to the right and left. By opening the blow mold 11, the molded container C can be taken out of the blow mold 11.

  The preform PF, the inner surface of which is coated with the coating layer S, is preheated to a predetermined temperature at which extensibility is exhibited using a heater (not shown) or the like, and then the upright posture in which the mouth PFa projects upward from the cavity 12. Is arranged on the blow mold 11.

  A nozzle unit 13 is provided above the blow mold 11 so as to be vertically movable relative to the blow mold 11. The nozzle unit 13 has a main body block 14 and a blow nozzle 15.

  The blow nozzle 15 includes a cylindrical nozzle body 15a having a smaller diameter than the inner diameter of the mouth PFa of the preform PF, and a large-diameter holding portion 15b formed integrally with the nozzle body 15a. It is formed integrally with a resin material or the like, and is fixed to the main body block 14 by fitting the holding portion 15b into the inner surface of the main body block 14.

  The nozzle body 15a is arranged coaxially with the cavity 12 of the blow mold 11, and engages with the mouth PFa of the preform PF mounted on the blow mold 11 when the nozzle unit 13 is lowered to a predetermined position. It has become. Reference numeral 16 denotes a sealing body for sealing between the nozzle body 15a and the mouth PFa.

  A supply path 17 is provided inside the main body block 14 and extends in the up-down direction coaxially with the nozzle body 15a. The supply path 17 is connected to the blow nozzle 15 at a lower end thereof.

  A pressurized liquid supply unit 19 is connected to the supply path 17 via a pipe 18. The pressurized liquid supply unit 19 can supply the pressurized liquid L pressurized to a predetermined pressure to the supply path 17 via the pipe 18.

  When the pressurized liquid L is supplied from the pressurized liquid supply unit 19 to the supply path 17, the pressurized liquid L is supplied from the supply path 17 to the inside of the preform PF disposed in the blow mold 11 via the blow nozzle 15. Supplied to Thus, the preform PF is liquid blow-molded by the pressurized liquid L into the container C having a shape along the cavity 12 of the blow mold 11.

  As the pressurized liquid supply unit 19, for example, one having a configuration using a plunger pump as a pressurization source is used.

  Inside the supply path 17, a seal pin 20 for opening and closing the supply path 17 with respect to the blow nozzle 15 is arranged. The seal pin 20 is formed in a cylindrical shape extending along the axis of the supply path 17, and is movable vertically with respect to the main body block 14 inside the supply path 17. On the other hand, a tapered closing surface 15c is provided on the upper surface of the holding portion 15b of the blow nozzle 15. When the seal pin 20 moves to the lower stroke end and the tapered surface 20a provided at the lower end of the seal pin 20 comes into contact with the closing surface 15c, the communication between the supply path 17 and the nozzle body 15a is cut off by the seal pin 20, and the supply is stopped. The passage 17 is closed with respect to the blow nozzle 15. On the other hand, when the seal pin 20 moves upward and the tapered surface 20a provided at the lower end of the seal pin 20 separates from the closing surface 15c, the supply path 17 communicates with the nozzle body 15a. Open state, that is, open state.

  Therefore, as shown in FIG. 2, the pressurized liquid supply unit 19 is engaged with the nozzle body 15a engaged with the opening PFa of the preform PF, the seal pin 20 is opened, and the supply path 17 is communicated with the blow nozzle 15. By operating the preform PF, the pressurized liquid L is supplied from the pressurized liquid supply unit 19 into the preform PF via the supply path 17 and the blow nozzle 15, and the preform PF can be subjected to liquid blow molding. Then, the container C containing the pressurized liquid L, that is, the erosion liquid therein, is manufactured by the liquid blow molding.

  The liquid blow molding apparatus 1 may have a configuration in which the extension rod 21 is slidably mounted in an insertion hole formed in the center of the seal pin 20. In this case, the extension rod 21 can be moved relatively vertically (axially) with respect to the seal pin 20, and moves downward (to the bottom of the cavity 12) with respect to the seal pin 20, as shown in FIG. By doing so, the bottom portion of the trunk PFb of the preform PF disposed in the blow mold 11 is pushed downward, and the trunk PFb is extended in the axial direction (vertical direction) inside the cavity 12. That is, by using the liquid blow molding apparatus 1 having the configuration in which the stretching rod 21 is provided, the preform PF placed in the blow mold 11 is stretched in the vertical direction using the stretching rod 21 while the pressurized liquid L is stretched. The container C can be manufactured by biaxial stretch blow molding for stretching in the radial direction.

  As described above, in the present invention, the preform PF, the inner surface of which is covered with the coating layer S, is subjected to liquid blow molding in the liquid blow molding step, so that the preform PF is formed into a container C having a predetermined shape containing an erosion liquid as a content liquid. can do. At this time, since the inner surface of the preform PF is covered with the coating layer S, the pressurized liquid L supplied to the inside of the preform PF does not contact the inner surface of the preform PF formed of polyethylene terephthalate. . Further, since the coating layer S has ductility and water insolubility, the coating layer S is stretched together with the preform PF without being dissolved in the pressurized liquid L during liquid blow molding, and is always pressed. The entire inner surface of the reform PF or the container C is covered. Therefore, the inner surface of the preform PF or the container C formed of polyethylene terephthalate can be always protected by the coating layer S during the liquid blow molding, whereby the inner surface is affected by the pressurized liquid L which is an erosion liquid. Can be prevented. Therefore, it is possible to prevent cloudiness (cloudiness) from occurring in the container C after molding, and to ensure the permeability of the container C after molding.

  For example, when a water-soluble coating is used as the coating layer, the coating layer is dissolved by the pressurized liquid supplied into the preform during liquid blow molding, so that the pressurized liquid L is eroded. When a liquid is used, the inner surface of the preform cannot be sufficiently protected from the erosion liquid. Further, when a coating film such as diamond-like carbon (DLC) which is hard and does not have sufficient ductility is employed as the coating layer, the coating layer cannot be stretched together with the preform during liquid blow molding. When an erosion liquid is used as the pressurized liquid L, the inner surface of the preform should be sufficiently protected from the erosion liquid because many portions where the coating layer is not provided on the inner surface of the preform or the container. Can not. For this reason, cloudiness occurs on the inner surface of the container, and the permeability of the container is impaired.

  On the other hand, in the present invention, since the inner surface of the preform PF is coated with the coating layer S having ductility and water insolubility, even when the erosion liquid is used as the pressurized liquid L, The inner surface of the preform PF formed of polyethylene terephthalate is reliably protected from the erosion liquid, and it is possible to prevent the inner surface of the molded container C from becoming cloudy and impairing the permeability of the container C.

  The present invention is not limited to the above embodiment, and it goes without saying that various changes can be made without departing from the spirit of the present invention.

  For example, in the above-described embodiment, it is preferable that the preform PF and the container C be transparent, but if the preform PF and the container C have transparency, the preform PF and the container C may be colored in a predetermined color. You can also. Even in this case, even if the above-described erosion liquid is used as the pressurized liquid L supplied to the preform PF, generation of white turbidity (cloudiness) due to the formation of fine irregularities on the inner surface of the container C is suppressed. Thus, the transparency of the colored container C can be ensured.

  Further, the blow molding apparatus for performing the liquid blow molding of the preform PF is not limited to the liquid blow molding apparatus 1 having the configuration shown in FIGS. 1 and 2, but various configurations can be used.

  Furthermore, in the above-described embodiment, the coating layer S is permeable, or does not have permeability when provided on the inner surface of the preform PF, but the preform PF is formed into a container. Although it is preferable that the resin is stretched together with the preform PF when the preform PF is stretched together with the preform PF, that is, after the container C is formed, the coating layer S is not limited to this. Also, those having no permeability can be used.

  Furthermore, in the present embodiment, the entire inner surface of the preform PF is covered with the coating layer S. However, at least only the inner surface of a portion corresponding to the trunk PFb of the preform PF is coated with the coating layer S. It is also possible to adopt a configuration in which

DESCRIPTION OF SYMBOLS 1 Liquid blow molding apparatus 11 Blow molding die 12 Cavity 13 Nozzle unit 14 Main block 15 Blow nozzle 15a Nozzle main body 15b Nipping portion 15c Closed surface 16 Seal body 17 Supply path 18 Pipe 19 Pressurized liquid supply portion 20 Seal pin 20a Tapered surface 21 Extension Rod PF Preform PFa Mouth PFb Body S Coating layer L Pressurized liquid (eroding liquid)
C container

Claims (4)

Preform molding step of molding a preform having at least an inner surface having permeability formed of polyester,
A coating step of coating the inner surface of the preform with a coating layer having ductility and water insolubility,
Have a, a liquid blow-molding process for molding a container having a predetermined shape the preform to supply internal to the pressurized liquid of the preform inside surface is coated by the coating layer,
The pressurized liquid contains at least one of an alkali component, a surfactant, and an alcohol component such as ethanol in a proportion of a predetermined weight concentration or more, and erodes the polyester to make the surface of the polyester cloudy. container manufacturing method comprising Rukoto using liquid.   The container manufacturing method according to claim 1, wherein the preform is formed of polyethylene terephthalate.   The container manufacturing method according to claim 1, wherein the coating layer is formed of polyvinyl butyral.   The container manufacturing method according to claim 1, wherein the coating layer is formed of polyvinylidene chloride.

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